In U.S. Patent Publication No. 2007/0198926, Jouget et al. disclose a resistive multi-point touch device, which includes an upper electrode layer and a lower electrode layer, respectively provided with a plurality of wires arranged in parallel and oriented in different directions. Insulating particles are distributed between the upper and lower electrodes to separate them from each other (a spacer). When the upper electrode layer is suppressed, portions of the wires on the upper electrode layer will be in contact with the wires on the lower electrode layer, wherein all wires on the lower electrode layer are grounded. The wires on the upper electrode layer are sequentially driven, while the wires on the lower electrode layer are sequentially sensed once for each one of the wires being driven on the upper electrode layer, thereby all intersecting points crossed by the wires on the upper and lower electrode layers can be sensed. As a result, when a wire being driven on the upper electrode layer is suppressed and in contact with the wire being sensed on the lower electrode layer, current will flow from the driven wire on the upper electrode layer to the sensed wire on the lower electrode layer, thus contact points can be determined by sensing signals on the wires of the lower electrode layer.
As shown in FIG. 1, when a finger suppresses the upper electrode layer, a group of intersecting points may be suppressed at the same time. This may cause the signal on the wires of the lower electrode to become smaller during subsequent sensing, so it is necessary to assign a different comparison value to each intersecting point in order to determine if an intersecting point is being suppressed when the signal is weak. However, such a method may render inaccuracy when the amount of intersecting points being suppressed is large. Obviously, the setting up and storage of comparison values for each intersecting point would take up a considerable amount of time and resources, and still the accuracy may not be satisfactory. Moreover, when the density of the wire increases with the increase of resolution, the frequency for sensing has to be correspondingly reduced.
Therefore, there is a need for a resistive multi-point touch device and method to improve the prior-art problems.